The present invention relates to an improvement of a mechanism to jet the processing liquid of a wire electric discharge machine, and to stably supply the higher flow velocity processing liquid to a gap between the work piece and a wire electrode.
Referring to FIG. 6, FIG. 7(a) and FIG. 7(b), the conventional wire electric discharge machine will be described. In FIG. 6, FIG. 7(a) and FIG. 7(b), the wire electric discharge machine is composed of: a bed 1 which is a base; a table 5 to fix a workpiece 3 processed by a wire electrode 2; a processing tank 7 to pool the processing liquid; an X axis drive section 13 to move the table 5 in the X axis direction, by moving an X axis table 9 by the drive of an X axis motor 8; a Y axis drive section 17 to move the table 5 in the Y axis direction, by moving a column 19 along the longitudinal direction of a lower arm 20 fixed on the base 1 by the drive of a Y axis motor 15; a Z axis drive section 21 fixed on the column 19 to move the table 5 in the Z axis direction; an upper wire guide 25 which is fixed on the tip portion of the Z axis drive section 21 and guides the wire electrode 2; a lower wire guide 30 fixed on the lower arm 20 through an insulation plate 26, on the vertical surface of the tip portion of the lower arm 20; a feeding section 60 which is housed in the lower wire guide 30 and feeds the electric energy to the wire electrode 2; and a supply and collection section to supply the wire electrode 2 and to collect it.
The lower wire guide 30 flows the processing liquid to the work piece 3 while guiding the wire electrode 2, and the lower end portion of the guide main body portion 33 having a collar is engaged with and fixed onto a guide attaching plate 31 having a passage to supply the processing liquid to the work piece 3 and a guide hole through which the wire electrode 2 passes. A hollow cylinder portion to guide the wire electrode 2 is provided on the guide main body portion 33, and a central hole of a disk-like straightening plate 35 having a plurality of holes to flow the processing liquid is engaged with and fixed to the cylinder portion, thereby, a pool 36 is formed between the outlet of the passage of the guide attaching plate 31 and the holes 35a of the straightening plate 35.
An upper auxiliary guide 38 to guide the wire electrode 2 is fixed to the inside of the upper portion of the guide main body portion 33, and a lower auxiliary guide 39 is also fixed to the inside of an auxiliary plate 37 fixed to a lower portion of the guide attaching plate 31. Incidentally, the guide attaching plate 31 and the auxiliary plate 39 are fixed onto a lower block 41.
A nozzle 40 to jet the processing liquid is structured such that: the inner peripheral surface is fixed onto the outer peripheral surface of the straightening plate 35, the bottom surface is fixed onto a top panel of the guide attaching plate 31, and the top panel of the collar is fixed by a pressure plate 43 through a spring 45, thereby, the spring 45 is compressed by the pressure of the processing liquid and the tip is elevated, and by stop of the supply of the processing liquid, the tip is returned in order to prevent the contact with the work piece 3. Incidentally, a pipe 50 is connected to an inlet of the guide attaching plate 31. Further, because the basic structure of the upper wire guide 25 is the same as the lower wire guide 30, the explanation will be omitted.
The feeding section 60 is composed of a feeding dies 62 to feed the electric energy to the wire electrode 2, and a dies pressing plate 64 to fix this feeding dies 62, and is electrically connected to the feeding dies 62 through the guide attaching plate 31 formed of the conductive material by a wire 70 from a power source, not shown.
The supply and collect portion of the wire electrode 2 is structured in such a manner that the wire electrode 2 passes through a pipe 89 through rollers 83, 85 and 87 which convert the direction of the wire electrode 2 wound around a wire bobbin 80, and is accommodated in a collection box 90.
The operation of the wire electric discharge machine structured as described above, will be described below referring to FIG. 6 and FIG. 7. Initially, the feeding energy is electrically fed via the wire 70 to the wire electrode 2 through the feeding dies 62, and while the discharge between the work piece 3 and the wire electrode 2 is being generated, and the table 5 is being moved to the X, Y, or Z axis, by operating the X axis drive section 23, Y axis drive section 17, and Z axis drive section 21, the work piece 3 is processed to the desired shape.
On the one hand, during processing of the work piece 3, the processing liquid passes through the passage from the pipe 50 to the guide attaching plate 31, passes through the hole 35a of the straightening plate 35 to stabilize the directionality of jetting, and lightens the curvature of the fluid on the basis of the generation of the eddy flow caused through the pool 36 or the like, and jets from the jetting hole 40a of the nozzle 40. Such the jetted high speed processing liquid is supplied to the gap (hereinafter, called electrode gap) between the work piece 3 and the nozzle 40, and the processing sludge is delivered and removed, and the processing is continued while continuing the discharge by keeping the normal electrode gap and resistance value constant.
However, the processing liquid of the wire electric discharge machine structured as described above, passes through the passage of the guide attachment 31 from the pipe 50, and after it is temporarily stays in the pool 36 and the pressure is increased, and it passes by being converted into the velocity energy by the hole 35a of the straightening plate 35, and stays in the space portion formed by the inner surface of the nozzle 40 and the straightening plate 35, and after it becomes the pressure energy, the high speed fluid is jetted from the jetting hole 40a of the nozzle 40 into the electrode gap as the velocity energy.
That is, because a form of the energy of the processing liquid is converted as many as 4 times in both of the velocity and pressure, the processing liquid gradually losses the holding energy at the inlet of the guide attaching plate 31, and the velocity energy jetted from the jetting hole 40a of the nozzle 40 is lowered. Accordingly, when the electrode interval becomes large, because the pressure of the processing liquid is decreased, and the disturbance in the jetting direction is largely changed, there is a problem that the processing becomes unstable.
Further, the straightening plate 35 decreases the curvature or deflection of the fluid due to the generation of the eddy flow of the processing liquid inside the pool 36, and it stably jets the processing solution so that the directionality of the processing liquid jetted from the jetting hole 40a of the nozzle 40 is directed upward rightly, however, there is a problem that it generates the large pressure loss.
The present invention is attained to solve the above problem, and to provide a wire electric discharge machine in which the pressure loss is small in the case of jetting the processing liquid from the nozzle.
In order to attain the object, in a wire electric discharge machine of the first aspect, a wire electric discharge machine in which a work piece is processed, while the processing liquid exists between the wire electrode and the work piece, and the discharge is being generated, the wire electric discharge machine is characterized in that a jetting nozzle to jet the processing liquid toward the work piece, and the wire guide portion which flows the processing liquid to the jetting nozzle, and guides the wire electrode into the bored hole, are provided, wherein the wire guide portion has a first passage to flow the processing liquid into the jetting nozzle, and a second passage to convert the direction of the processing liquid to be flowed into the first passage, wherein the first and the second passages are plural.
The wire electric discharge machine of the second aspect is characterized in that: a feeding dies which is engaged with a cutout in which a side portion of the wire guide portion is cut out, and fixed to it; and which applies the voltage onto the wire electrode, and has the third passage constituting the first passage in the inside of the dies, is provided.
The wire electric discharge machine of the third aspect is characterized in that the vicinity of an outlet portion of the first passage is inclined toward the jetting hole of the jetting nozzle.